Check return result from Py_InitModule*().  This API can fail.

Probably should be backported.
diff --git a/Python/import.c b/Python/import.c
index f284ff4..8bd25f7 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -2817,6 +2817,8 @@
 
 	m = Py_InitModule4("imp", imp_methods, doc_imp,
 			   NULL, PYTHON_API_VERSION);
+	if (m == NULL)
+		goto failure;
 	d = PyModule_GetDict(m);
 
 	if (setint(d, "SEARCH_ERROR", SEARCH_ERROR) < 0) goto failure;